A successive approximation analog-to-digital converter using a capacitance array is being used because of its relatively simple circuit configuration. The successive approximation analog-to-digital converter uses the capacitance array to produce voltage with levels varying as the nth power of 2 (2n) and successively compares the voltage with the voltage of an input analog signal, thereby digitizing the analog signal. Related art is discussed in Japanese Laid Open Patent Publication No. 2007-142863.